High or low fluid flow signalling apparatus

ABSTRACT

Signalling apparatus for producing pressure pulses in the stream of well drilling fluid in which the fluid flows through a pulse ring assembly having axially spaced rings cooperative with a knob reciprocable though said rings to provide restricted flow paths productive of the fluid pressure pulses in the drilling fluid stream in a number representative of the disposition of the well drilling string in the well bore in the vicinity of the drill bit, and in which a replaceable flow bushing is employed to provide a selected flow area between the pulse ring and the knob when the knob is in its normal position responsive to the influence of drilling fluid pressure thereon, so that movement of the knob to said position is assured under the prevailing flow rate. Such apparatus in which a gravity responsive pendulum system is utilized to determine the extent of movement of said knob and releasable latch means connect the gravity responsive means to the knob.

United States Patent [72] Inventor Raymond G. Taylor, Jr.

Los Angeles, Calif. [2|] Appl. No. 862,109 22] Filed July 17, 1969 Division of Ser. No. 73" 7,96 0, June 18,1968, Pa t. 3,4 3,035.

I45] Patented Mar. 23, 1971 [73] Assignee Byron Jackson, Inc.

Long Beach, Calif.

[54] HIGH OR LOW FLUID FLOW SIGNALLING APPARATUS 5 Claims, 10 Drawing Figs. I [52] US. Cl 33/205, 175/45 [5 l] Int. Cl. G011: 9/00 [50] Field of Search 33/205,

[56] References Cited 0 UNITED STATES PATENTS 3,440,730 4/ 1969 Alder 33/205 3.457.654 7/1969 Alder Primary ExaminerLeonard Forman Assistant Examiner-Steven L. Stephan AttorneysDonald W. Banner, Lyle S. Motley, C. G. Stallings and William S. McCurry ABSTRACT: Signalling apparatus for producing pressure pulses in the stream of well drilling fluid in which the fluid flows through a pulse ring assembly having axially spaced rings cooperative with a knob reciprocable through said rings to provide restricted flow paths productive of the fluid pressure pulses in the drilling fluid stream in a number representative ot'the disposition of the well drilling string in the well bore in the vicinity of the drill bit, and in which a replaceable flow bushing isemployed to provide a selected flow area between the pulse ring and the knob whn th e knobTs in its nor'nizil position responsive to the influence of drilling fluid pressure thereon, so that movement of the knob to said position is assured under the prevailing flow rate. Such apparatus in which a gravity responsive pendulum system' is utilized to determine the extent of movement of said knob and releasable latch means connect the gravity responsive means to the knob.

HIGH OR LOW FLUID FLOW SIGNALLING APPARATUS This application is a division of application Ser. No. 737,960, Raymond G. Taylor, .lr., filed Jun. 18, 1968, now US. Pat. No. 3,468,035,.issued Sept. 23, I969.

BACKGROUND OF THE INVENTION In general, signalling drift indicators of the type here involved are adapted to be disposed in adrill collar sub above the drill bit of a well drilling string. The instrument includes an elongated housing containing clean oil, and internal pressure is balanced with external pressure ;by a floating divider at the lower end of the instrument. At the upper end of the housing is a pulse ring attachment through which drilling fluid flows during drilling. Reciprocable in the upper end of the housing is a shaft having a knob which passes upwardly through the pulse rings upon extension of the shaft from the housing and which, responsive to flow of drilling fluid, will force the shaft downward within the housing. As the knob passes downward through the pulse rings it cooperates with them to provide restrictions to flow. Such movement is retarded" so that the successive restrictions cause distinct .pressure pulses which will travel through the column of-fluid to the earths surface, where the signals may be recorded. Gravity responsive means are provided in the housing for limiting shaft extension in accordance with the angle from vertical at which the. housing is disposed when the circulation of drilling fluid is halted. Thus, the pressure pulses recorded. at the. surface are indicative of the angle of the well in the region of the drill string sub in which the instrument housing is installed.

Such apparatus may include a coding system including a rod, stop members selectively expandable by the rod, and a stop carried by the shaft and engageable with the expanded stop members. The coding rod is controlled by the gravity responsive means so that the ultimate travel of the shaft, and thus the knob through the pulse rings, is directly related to the angle of the instrument. Such an instrument therefore produces a pulse for each increment of the total angle which the instrument may measure. I

In the use of such apparatus it has been determined that it is desirable to disconnect the gravity responsive means from the shaft which supports the pulse knob after the gravity responsive means has performed its stop function, whereby to protect the gravity responsive means against undue wear or destruction.

An apparatus typical of that generally described above is illustrated and described in the application for US. Letters Pat. filed by Robert L. Alder on Jul. 1, I966, Ser. No. 562,146, now US. Pat. No. 3,457,654, issued Jul. 29, I969.

One of the difficulties encountered in the utilization of such apparatus is the fact that the force relied upon to move the pulse producing knob downwardly to its lowermost position during the drilling operations is derived from the effect of drilling fluid pressure upon the knob; but inasmuch as different wells are drilled at different drilling fluid flow rates, the pressure differential across the pulse'knob is not always the same. However, the flow restrictionproductive of the differential pressure across the knob has been uniform in the signalling devices and so also have the internal forces within the apparatus tending to resist the downward movement of the knob. Accordingly, in some instances the pressure acting upon the knob to move the same downwardly is insufficient to overcome the forces tending to resist such downward movement, resulting in the fact that the knob supporting shaft may project upwardly from the instrument housing and be subjected to the erosive action of the drilling fluid on surfaces which are required to effectively cooperate with sealing means to prevent intrusion of drilling fluid into'the instrument housing. Other problems exist in respect of the means for releasing the gravity responsive means from the knob supporting shaft inasmuch as, in order for such releasing means to be reconnected, it is necessary that the shaft in response to fluid pressure acting on the knob move fully to its lowermost position;

and. if the knob is not in its lowermost position when the cir-' culation of drilling fluid is interrupted to permit upward travel of the knob, then erroneous indications ofthe angular disposition of the drill string may be produced when the circulation of drilling fluid is resumed.

SUMMARY With the foregoing in mind, the present invention provides apparatus for producing signals in the stream of drilling fluid in which a pressure responsive knob is normally held in a lowermost position by the flow of drilling fluid but is movable upwardly through pulse rings when the flow of drilling fluid is interrupted so that, upon resumption of drilling fluid flow, pressure pulses will be produced in the fluid stream indicative of the disposition of the instrument within the well bore, wherein the apparatus may be preconditioned for operation in the drilling of wells over a wide range of drilling fluid flow rates while assuring that the knob will be subjected to sufficient pressure by the drilling fluid stream to cause its downward movement to the limit of its permitted downward travel.

More specifically, the apparatus is adapted to be preconditioned so as to assure downward movement of the knob and resultant connection of releasable connector means which are adapted to connect the gravity responsive means to the mechanism whichcontrfols the upward movement of the knob.

In accomplishing the foregoing, the present invention provides a replaceable bushing having an opening therethrough for the reception of the pulse producing knob of the apparatus. whereby the flow area between the bushing and the knob can be preselected so as to cause the production of sufficient pressure differential across the knob under given fluid flow conditions so as to assure that the knob-will be forced to its lowermost position. As results of the fact that the knob will be forced to its lowermost position, the knob supporting shaft is protected against the erosive action of the drilling fluid and releasable connector means in the instrument are effectively reconnected. The bushing is composed of wear-resistant material so as to minimize the effects of fluid erosion.

Other advantages and objects of .the invention will be hereinafter described or will become apparent to those skilled in the art, and the novel fcaturcs'of the invention will be defined in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary view partly in vertical section and with certain parts shown in elevation, illustrating a drift indicator instrument installed in a drill collar sub, the shaft being in its down position'and the pendulum being on its seat;

FIG. 2a is an enlarged fragmentary detail view in longitudinal' section showing the upper end of the instrument of FIG. 1, minus the pulsering assembly, and showing the upper portion of the coding system;

FIG. 2b is a downward extension of FIG. 2u,showing the upper actuating means for the angle adjuster and showing the intennediate portion of the coding system;

FIG. 20 is a downward extension of FIG. 2!), showing the lower portion of the angle adjuster, and showing the lower portion of the coding system including the pendulum release means;

FIG. 2d is a downward extension of FIG. 2c,showing the pendulum seat, with the pendulum seated thereon, and showing the lower instrument support and. the internal-external pressure balancing divider and the instrument fluid transfer restrictor and bypass;

FIG. 3 is an enlarged fragmentary view in vertical section showing the pendulum release system, with the pendulum connecting rod connected to the coding rod and in the extreme upper position just prior to release;

FIG. 4 is a fragmentary view in vertical section correspond ing to FIG. 3, but showing the pendulum connecting rod released and urged downward, ascompared to FIG. 3. to allow reseating of the pendulum, and showing, in broken lines, the pendulum release means moved downward for reconnection with the connecting rod;

FIG. Sis a view taken on the line -5 of FIG. 3;

FIG. 6 is a view of the latch mechanism on an enlarged scale taken on the line 6-6 of FIG. 4; and

FIG. 7 is an enlarged fragmentary view in longitudinal section illustrating the pulse tube mounting and the replaceable bushing of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. I it will be seen that the drift indicator assembly of the invention is installed in a sub or length of drill collar S which is, as customary, adapted to be mounted in a string of drill pipe so as to conduct drilling fluid downwardly through the drill collar sub S to the bit, not shown, and the fluid then flowing upwardly outside of the drill string to the earth's surface. This assembly comprises an instrument housing generally denoted I having at its upper end a pulse ring sleeve R- and at its lower end a bottom support B whereby the housing I is supported top and bottom in the sub S, and drilling fluid may flow through the sub 5 about the housing I.

The pulse ring sleeve R has an enlarged end flange 2 which shoulders and is sealed in a seat 3. At its lower end (FIG. 7) the pulse ring sleeve R has an outwardly extended flange 5a which seats upon the upper end of a cylindrical support 5 which is connected to a central hub 4 and provides windows 6 so that fluid may pass through the sleeve R. The hub 4 is suitably mounted on the upper end of the instrument I so as to support the pulse ring sleeve R thereabove, this mounting being preferably like that more specifically described in the application for US. Letters Pat. Ser. No. 56l,637, filed Jun. 29, I966, now Pat. No. 3,526,04l,issued Sept. 1, I970. The flange 5a of the pulse ring sleeve R is removably connected to the tubular member 5 by suitable means, such as fasteners 5h. Within the cylindrical member 5 is a bore 5c providing an inwardly projecting shoulder 5d, this shoulder 54 and the lower end 5e of the pulse ring sleeve R defining an annular space for reception of a replaceable bushing A. This bushing A may be suitably hardened or composed of erosion-resistant material so that its inner cylindrical wall 5f is resistant to the erosive effects of drilling fluid flowing therepast. At its lower end the bushing A is provided with a downwardly extended lip 5g having an outwardly flaring or beveled surface 5h leading into the cylindrical member 5. Within the sleeve R is a series of axially spaced pulse rings 7, each of which is adapted to cause a pressure pulse in the fluid stream passing therethrough, as will hereinafter appear. Between the rings 7 are axially extended and angularly spaced ribs 8 forming abutments in the spaces between the ribs, these abutments extending substantially to the inner annular surfaces of the rings 7 from the circumferentially extended walls 8a between the pulse rings 7. The diametrical distance between the walls 811 is, in the illustrative embodiment, greater than the diameter of the cylindrical wall 5f of the bushing A for reasons which will hereinafter become apparent, but the wall 5f has a selected diameter which in some cases may be substantially equal to the diameter of walls Bottom support B has an outer rim 9 and a hub 10 on which the rim 9 is supported by webs II forming therebetween flow passages at the lower end of housing 1. A port 12 is provided in the hub 10 so that fluid finds access to the housing I at its lower end.

The housing at its upper end has reciprocably mounted thereon and extensible therefrom a shaft 13 having at its outer extremity a head or knob 14. Within housing I is a spring 15 which normally biases shaft 13 upwardly out of the housing I, thereby causing the head 14 to be moved upwardly through the pulse rings 7. However, the flow of drilling fluid downwardly through the pulse ring sleeve R will cause the head 14 to move downwardly, and the flow of fluid downwardly through the annular space 51' between the knob and the bushing A will provide a pressure differential acting on the knob I4 to hold the same in its lowermost position in abutting engagement with the upper end of the instrument I. Thus, during circulation ofdrilling fluid the shaft I3 and knob I4 will remain as shown in FIGS. I and 7. but when such circulation is halted, the shaft will be forced upward or outward and the head will move upward through the rings 7. Such circulation ofdrilling fluid is ceased each time an additional length of drill pipe is to be added at the earth's surface, and otherwise as desired. When circulation is resumed, pressure pulses are caused as the knob I4 passes through the rings 7 due to the restriction in flow area, and such pulses are detectable at the earth's surface by a typical pressure gauge or pressure recorder.

In order that the upward movement of the shaft I3 will be limited in accordance with the angle at which the housing I is disposed, gravity responsive means including a pendulum generally denoted at I6 is adapted to selectively engage pendulum stop means I7 as the pendulum moves upwardly. In order to retard downward movement ofthc shaft l3 so that. as previously indicated, the resultant pressure pulses will be distinct and adequately spaced, means generally indicated at I8 are provided for retarding fluid displacement through the pendulum seat 19. At the lower end of the housing I is a divider piston 20 shiftable to balance internal fluid pressure and external drilling fluid pressure and so as to enable the transfer of fluid through the retarding means 18 as the shaft [3 displaces fluid downwardly and the upward transfer of fluid through a check valve 22 as the shaft I3 is urged upwardly.

In order to change the relationship between the stop means I7 and the pendulum I6, means are provided for shifting the stop means axially in housing I. In this connection the stop means I7 is connected by rods 23 to adjuster means 24.

Referring now more particularly to FIGS. 2a through 2d. the details ofthe structure will be more fully explained.

The instrument housing I includes an upper tubular section 30 having an upper shaft guide 31 threadedly mounted therein. Shaft guide 3I has a seal and wiper means 32 and 33. respectively, engageable with the shaft I3. At the outer or upper extremity of the shaft, the knob I4 is supported by means of a knob bushing 34, a pin 35 connecting the bushing to the shaft, and a snap ring 36 retaining the knob on the bush ing.

As seen in FIG. 2c, the upper housing section 30 is threaded to a lower housing secton 37 to the lower end of which is connected to the hub I0 of bottom support B, as shown in FIG. 2d. Within the lower housing section is the divider piston 20 which has a skirt 38 adapted to extend into the hub I0. Mounted in the skirt 38 is a hollow piston guide stem 40, at the lower end of which is a filler plug 4|. whereby the housing may be filled with clean oil or the like. A spring 42 seated in hub I0 is provided to normally bias the piston 20 upward, but essentially the piston 20 serves to apply pressure to the internal fluid equal to external fluid pressure and to move axially to allow extension of the shaft I3 from the housing.

Disposed above the piston 20 in lower housing section 37 is an orifice block 43, retained in place by a lock ring 44 and having a downwardly extended guide tube 45 slidably receiving the piston guide stem 40 ofthe piston. Supported by an upwardly extended tubular part 46 on the block 43 and within guide tube 45 is an orifice disc support 47 having therein a stack of orifice discs 48 retained in place by a ported plug 49. At one side of block 43 is the upwardly opening ball check valve 22 and at another location in the block 43 is a downwardly opening spring loaded relief valve 50. Thus, the orifice block, the valve 22 and the orifice discs 48 constitute means for retarding downward flow of housing fluid through the block 43, while enabling comparatively free upward flow of housing fluid, as the shaft I3 is extended from the housing I and forced back into the housing during operation of the instrument. The valve 50 serves to relieve pressure in the event that such relief may be necessary.

The block 43 also supports the aforementioned pendulum seat 19. This seat I9 comprises a conical center 5] having an upstanding guide skirt 52. The seat center has a ported stem 53 and means are provided for adjustably supporting the stem 53 and hence the seat 19 within the upper end of block part 46. Such means in the illustrative embodiment comprise a spider 54 in which the stem 53 is threaded, and a lock 55 engageable with the spider.

The pendulum 16, as shown in FIGS. 1 and M, is adapted to seat in the pendulum seat I9 when, as shown in FIGS. I and 2a, the shaft 13 is in the downward position. The shaft is connected to the pendulum by meanswhich (I) allow upward movement of the shaft a distance inversely related to the upward travel of the pendulum, and (2) by means which, upon the pendulum reaching the upper limit of its travel, will cause release of the pendulum so that it will be freed to return to its seat. I

The first-mentioned means includes a longitudinally extended coding rod 60 which is reciprocally disposed in a tubular guide and stop ball support 61. The guide 6I is connected to and essentially constitutes a portion of the upper housing section 30, and, as best seen in FIGS. 3 and 4, the guide is supported at its lower end in a coding rod stop tube 62 which is fonned as an upward extension of a block 63 which in turn is secured as by fasteners 64 to the lower end of the upper housing section 30. More specifically, the guide 61 seats at its lower end on a washer 65 which shoulders at 66 in the upper end of the tube 62; and, in upwardly spaced relation to the washer 65, is a second washer 67 fastened in the tube 62v by lock ring 68, the lower end of the guide 61 extending through washer 67 and having a lock ring 69 which engages beneath the washer 67. Thus it is apparent that while the guide 6] is assembled with the tube 62 prior to connection of the block 63 to the lower end of housing section 30, means are provided so that the ultimate assembling of these components results in the guide 6I being rigidly and concentrically supported within the upper housing section 30.

The coding rod 60 previously referred to is composed of an upper end section 70 slidably disposed within the guide 61.

Beneath the upper end 70 is an axially spaced series of reduced stem sections 7I and thimbles 72a, 72b, 72c, 72d 72eand 72f. Beneath the lowermost thimble 72fis aconnector 73 which connects the upper coding rod section 70 to a lower coding rod section 74, the latter extending downwardly through the guide 61 and the guide supporting washers 65 and 67 into the coding rod stop tube 62. At its upper end, coding rod section 70 has a centralizing guide 70a secured thereto and slidably engaged in the shaft 13, this guide being perforated to permit bypass of fluid within the instrument. Above the guide 70a is a coil spring 70h freely disposed in shaft I3 so as to engage and bias the coding rod downward when the shaft is in its downward position, as shown'inFIG. 2a. As shown in FIGS. 2band2 c, there is anothercoil spring 60a which surrounds the lower coding rod section 74 within rod guide 61 and engages at its upper end with connector 73 and at its 6 sets of such balls respectively designated from top to bottom, as viewed in FIGS. 2a and 2b, 75a, 75b, 75c, 75d, 75e and 75f, adapted to be moved outward by thimbles 72a'-.-72f, respectively. The balls are disposed in openings 76 in the rod guide 61=' so that the latter also constitutes a ball support. The sets of balls are cammed outward upon. engagement by the respective thimbles 72a-72f into annular space 13a defined by the guide 61 and the shaft 13. Within the shaft 13 (see FIG.

2b) is a stop 77 which definesthe bottom of the just-mentioned annular space 13a, and essentially this stop forms a portion of the shaft I3 which will limitupward movement of the latter, under the influence of spring I5,'upon engagement with one of the sets of stop balls 75a-75f, or upon engagement with a stop ring 75- carried by tube 6| in spaced relation above stop balls 750 (FIG. 20), thus selectively limiting upward movement of the knob I4 with respect to the pulse ring sleeve R.

Essentially the stop shoulder 77 is a portion of the shaft 13, but in the specifically shown structure the shaft I3 incorporates means for allowing freedom of upward movement of the shaft independently. of the stop shoulder 77 in order to relieve the stop shoulder and stop balls from excessive loading in the event of back flow of drilling fluid through the drill collar S, as well as during running of the drill string into the well bore following the changing of drill bits. Accordingly, as shown in FIGS. 2b and 2c, the shaft I3 is reduced in diameter at the point of its connectionwith a downwardly extended shaft cxtension 80. If desired, the shaft I3 may be provided with an enlarged sleeve 80a above the shaft-extension 80 to stabilize the shaft assembly within the body section 30. Concentrically disposed about the downward shaft extension 80 is a spring coupling sleeve 81 having an upper outwardly projecting flange 82 engaged by the upper end of a shaft biasing spring 15. The lower end of the latter abutting, as shown in FIG. 20. with the block 63. The just-mentioned flange 82 also abuts with the larger diameter upper shaft section so that the shaft I3 is biased upwardly. At its lower end the spring coupling sleeve SI, as seen in FIG. 2 c, is connected between a pair of snap rings 84 with an internal sleeve'85 which is disposed within the downward shaft extension 80. Thus it will be seen that the shaft extension 80 is free to move upwardly relative to the spring coupling sleeve 8! and the connected internal sleeve 85, but the spring I5 acts to bias the shaft I3 upwardly through the intermediary of the spring coupling sleeve 81 and internal sleeve 85, the latter having at its upward extremity the above-mentioned stop shoulder 77. Therefore, the extent of upward movement of the shaft I3 and the knob I4 under the influence of the spring 15 is limited by the stop 77, even though the shaft may be free to move further upwardly in response to the influence of fluid flow through the drill collar S.

Thus it will be apparent that if the balls 75f be cammed into the path of stop 77, the shaft l3 will be limited in its upward travel under the influence of spring I5 to a position at which the knob I4 is disposed between the lowermost and the next above pulse ring 7. As the shaft 13 is allowed further increments of upward movement then the knob I4 will correspondingly be allowed further upward movement, a distance equal to another pulse ring per increment of shaft movement. Thus if the stop 77 is allowed to pass all the sets of stop balls 75f through 75a but engages stop ring 75, the knob I4 will he allowed to travel a distance equal to the spaces between 7 pulse rings as a result of which downward movement of the knob caused by drilling fluid flow will cause the production of 7 pressure pulses or signals which will travel through the column of drilling fluid to the earth's surface for detection or recordation as an indication of the angle-at which the housing I is disposed within the well bore. As previously described, the gravity responsive pendulum and the cooperative pendulum stop means I7 serve to limit upward movement of the coding.

rod 60 so as to cause the projection of the appropriate set of stop balls 75a through .75f to limit upward movement of shaft 13. However, as mentioned above in accordance with one of the objectives of the invention, shaft I3 is releasably connected to the pendulum as will now be described and as is more particularly illustrated in FIGS. 24:, 3 and 4.

In prior instruments of the type here involved, and more particularly in instruments as specifically shown in US. Let-- ters Pat. No. 3,176,407, the gravity'responsive pendulum is directly connected to the coding rod. In the present construction, however, the coding rod 60 is relcasably connected to the pendulum 16 so that the shaft I3 is also releasably connected to the pendulum.

Slidably disposed within the coding rod stop tube 62 and within the block 63 is a connecting rod 90, to the lower end of which the pendulum is freely universally connected as by a pair of bails 91. At its upper end the connecting rod 90 is provided with a seat 92 formed within a cuplike female connector member 93 which has at its upper end a latch shoulder 94. Releasably engaged in the seat 92 is a latch mechanism comprising a body 95 having a reduced head 96 disposed in the seat 92 and within the latch shoulder 94 of the latter. Pivotally supported by the body 95 is a dog 97 having a latch finger 98 which is biased by spring 99 outwardly into latching engagement with the shoulder 94. The dog 97 also comprises a stop finger 100 having a laterally outwardly projecting end 101 which, when the latch finger 98'is engaged with the shoulder 94, as seen in FIGS. 2c and 3, is held in a retracted position within a slot in the body 95 in which the dog is pivotally mounted. The finger 100 of the dog also has an inward projection 102 beneath which is engaged an annular flange 103, which is, in the illustrative structure, provided on a thimble 104 suitably secured to the lower end of the coding rod 60. The thimble 104 is disposed within a bore 105 in the latch body 95 so as to enable limited relative upward movement of the coding rod, such upward movement being limited by a flange 106 on the thimble and a snap ring 107 within the bore of the body. Beneath the body 95 and projecting downwardly from the head 96 is a stem 108. This stem extends into a bore 109 in the connecting rod 90 and is surrounded by a spring 110 seated in the bore 109 and providing a force normally tending to separate the latch body from the connecting rod. The force of the spring 110 combined with the friction of the latching finger 98 with the latching shoulder 94 provide a holding force which must be overcome by the tendency of the coding rod 60 to move upwardly beyond a point at which upward movement of the connecting rod is arrested. Such a force tending to move the coding rod upwardly is provided by the coding rod actuator spring 60a previously described.

In accordance with the present invention, the coding rod 60 is to be released from the pendulum connecting rod 90 when the coding rod has reached the limit of the desired upward travel, that is, a location at which one or another of the sets of locking balls 75a75f has been displaced outwardly by thimbles 72a72f so as to preclude movement of shaft stop 77 upwardly beyond the outwardly projecting stop balls, or when the thimbles are so disposed that none of the stop balls are projected and shaft stop 77 will pass all of the balls and engage stop ring 75. Thus, means are provided to cooperate with the latch mechanism when the connecting rod 90 is released to limit further upward movement of the coding rod 60. In the illustrative embodiment, the coding rod stop tube 62 is provided with a vertically spaced series of stops 175, 1750, 175b, 175e, 175d, 175s and l75f which are respectively adapted to be engaged by the outward projection 101 on the stop finger 100 of the dog 97, when the latter is cammed outwardly by the thimble 104 responsive to further upward movement of the coding rod 60 after upward movement of the latch body 95 has been arrested either by engagement of the pendulum 16 with the pendulum stop means 17 or upon engagement of the latch body 95 with the washer 65 adjacent the top of the coding rod stop tube 62. Stops l75-l75f are provided by forming recesses in alignment in the stop tube 62. Means are provided to maintain alignment of the dog 97 with the recesses, and such means may comprise a pin 940 on latch member 95 slidable in an elongated keyway 94b in stop tube 62 (FIGS. 3, 4 and 6).

it will be noted that the spacing of axial stop balls 75a75f relative to the thimbles 72a72f, as shown in FIGS. 2a and 2b, is such that none of the stop balls will be projected outwardly into the path of shaft stop 77 when the coding rod has traveled upwardly the minimum extent, but the latch balls 75f will be projected outwardly into the path of stop 77 when the :oding rod has traveled upwardly to the maximum extent, that s, when the latch body 95 abuts with the washer 65 as previ- )usly described. As a result, the shaft 13 will be allowed to move upwardly a minimum extent when balls 75] are projected outwardly and a maximum extent when none of the balls 75u-75f are projected outwardly. This inverse relation- .ship as just described results in a direct relationship between the angle at which the housing is disposed relative to the gravity responsive pendulum when the upward motion of the pendulum is arrested and the extent of upward travel of shaft 13. More particularly, there is a resultant direct relationship between the number of pulse rings through which the knob 14 will pass upwardly and the number of pressure signals produced when the knob is forced downwardly by the flow of drilling fluid and the angle at which the housing I is disposed. Therefore, in respect of each increment of angular deviation there will be produced one pressure signal, and in a manner which will be hereinafter described, the range of angular deviation at which the instrument will respond may be adjusted so that the sensed deviation may be, for example, in increments of A ranging from 0 to 3-92 in the illustrative embodiment or in increments of I? ranging from 3-99 to 7, etc.

Referring now to FIG. 3, it will be noted that connecting rod and the latch mechanism comprising the member 94 and body have been moved from the position shown in FIG. 21' to the upward permissible limit of travel of the latch body 95, as would occur upon cessation of the circulation of drilling fluid downwardly through the drill string. Such upward movement, it will now be understood, will be caused by the force exerted by spring 15 upon the spring coupling sleeve 81 (FIG. 2b) which has caused the shaft 13 to move upwardly and the force applied by spring 6011 to move the coding rod 60 upwardly (FIG. 2b). It will now also be understood that the gravity responsive means comprising the pendulum 16 and the pendulum stop means 17 will permit the illustrated upward movement of the latch body 95 by reason of the fact that the instrument housing 1 is in essentially a vertical disposition, in the event that the instrument is set to detect angular deviation in the range of (1 to 3-5? as just-mentioned above. Under these circumstances, the upper end of body 95 will abut with washer 65 to limit further upward movement of the interconnected latch body and connecting rod 90. At this point, however, the coding rod biasing spring 6011 will cause further upward movement ofthc coding rod 60. As a result. the flange 103 on thirtible 104 will exert an outward camming action on the inward projection 102 of finger on the dog 97. Thus, the latch finger 98 of the dog will be released from the latch shoulder 94 and the outward projection 101 of dog finger 100 will be displaced into the recess 17Sf. Two things occur under the conditions just described, namely (1) responsive to the release of the latching finger 98 from shoulder 94, spring 110 will bias the connecting rod 90 downwardly from the position shown in FlG. 3 to that shown in H6. 4, and (2 further upward movement ofthe coding rod 60 will be prevented by engagement of the outward projection [01 in the recess l75f combined with engagement of flange 106 on thimble 104 with snap ring 107 carried within the bore ofthe latch body 95. Therefore, in accordance with one of the objectives of the invention, the relationship between the coding rod 60 and the stop shoulder 77 on the shaft is established, and simultaneously, the conneeting rod 90 is released so that the pendulum 16 is permitted to move downwardly into engagement with the seat 19. By virtue of the structure just described which permits the release of the pendulum from the coding rod, the pendulum 16 and stop means 17, hereinafter to be more specifically described, and protected against damaging impact loadings and resultant wear which has been found in the operation of conventional instruments to result in inaccurate readings of angular deviation. Furthermore, it will now be understood that the bails 91, in order to enable free pendulum movement, must be delicate as compared with the pendulum 16 and the stop means 17, and the release of the pendulum 16 from the coding rod also reduces the load applied to the bails tending to deform the same. The releasing operation just described resulting from engagement of the latch body 95 with washer 65, will also occur in the event that the pendulum 16 is stopped by the stop means 17 at any selected lower location, the significant point being that the upward movement of the latch body 95 is arrested so that a further slight movement upward of the coding rod 60 will effect camming outwardly of the stop finger 100 of the dog 97, and, as previously described, the pendulum 16 is adapted to engage the stop means 17 at spaced locations as a function of the deviation of the instrument housing I from vertical.

In any event, following release of the pendulum from the coding rod, resumption of the circulation of drilling fluid downwardly through the drill collar S, which results in downward movement of knob 14 and shaft 13, will cause reengagement of the releasable latch means os that the connecting rod 90 will again be connected by dog 97 to the latch body 95. Thus, as shown in broken lines in FIG. 4, the coding rod 60 will be moved downwardly to the extent that the thimble 104 in the bore 105 will force the latch body 95 downwardly against spring 110. Under these circumstances, the inward projection 102 of finger 100 of the-dog 97: will be freed to move inwardly into the reduced section of thimble 104 lying between the flange 106 and flange 103. As a result, the latch body 95 will be freed for downward movement to the position shown in broken lines in FIG. 4, at which the latch finger 98 will be cammed inwardly by the latch shoulder 94 so that the finger 98 will pass over the shoulder 94 to be reengaged with the latter. For the purpose of permitting the camming action of shoulder 94 on the latch finger 98, the coding rod stop tube 62 is provided with an elongated slot 62a aligned with recesses 17S-175f, into which the outward projection of finger 100 on dog 97 may extend during the just-mentioned camming action. The slot 62a is elongated was to allow for tolerance in the manufacture of components. f"

As previously indicated, in accordance with one of the fea tures of the present invention, means areprovided for adjusting the bail connection between the connecting rod 90 and pendulum 16, thus, as best seen in FIG. 3, the bails 91 comprise an upper bail wire 91a and a lower bail wire 91 h, each formed to provide a loop coengaged with the other. The bail 91a is mounted in a support 191a which extends into a bore 1920 in the lower end of the connecting rod 90. The support 191a has at its inner end a threaded stem 193a for adjustably positioning the support 191a in the bore 192a. Support 1911: is provided with a pair of diametrical openings, one of which is shown at 194a and into which a suitable tool may be inserted so as to deform the bail wire to prevent its removal from the support 191a. The position in which the support 191a is to be fixed may be determined and fixed by. insertion of asuitable locking element such as a cotter pin 195a or the like. In a similar fashion, the bail 91b is mounted in the support 191!) and the support 191!) is provided with openings 194!) to enable deformation of the bail to prevent its removal from the support 19111. In addition, this latter support has a threaded end 1931) engaged in the pendulum 16 so as to adjust the position of support relative to the pendulum 16. As in the case of support 191a, support 191!) may be fixed in adjusted position by a cotter pin 1951) which extends throughthe support 191b By virtue of this adjustable pendulum supporting structure, the relationship of the pendulum 16 to the connecting rod 90 may be adjusted to maintain a stable but substantially friction-free universal connection between the connecting rod 90 and the pendulum 16 so that the pendulum 16 may freely swing relative to the connecting rod 90 to any desired angular disposition relative to the stop means 17 and so that upward movement of the pendulum 16 will be arrested at a precise position representative of the angular disposition of the housing I.

It will be noted, as seen in FIGS. 1, 2c and 2d, that the stop means 17 comprises a supporting sleeve 17a connected to the above-described adjuster rods 23 by means of pins 17b. Adjacent the bottom of sleeve 17a is a stop ring retainer 170 held in place by a snap ring 17d. Intermediate the retainer 17c and the upper end of the sleeve 17a is a series of angular stop shoulders of progressively diminishing diameter. Preferably such shoulders are provided on a series of stacked stop rings 17a. In the illustrative embodiment there is an upper stop shoulder 275e FIGS. 1, 2c, and 3) provided by the uppermost stop ring 172 and progressing downwardly are stop shoulders 275d, 2751;, 275b, 275a and 275 of progressively increasing diameter. Thus, if upper movement of the pendulum 16 is arrested by stop shoulder 275e, outward projection 101 of dog 97 will engage with the stop at 175e, in coding rod stop tube 62 and balls 752 (FIG. 2a) will be caused to project into the path of stop 77 (FIG. 2b) of the shaft 13. The same relationship exists between each of the stop shoulders 275 through 275d, dog stops 175 through 175d and stop ring and balls 75a through 75d so that, while the upward travel of the pendulum 16 will be inversely related to the angular deviation of the instrument housing I, the permitted upward travel of the cod ing rod 60 and hence the permitted upward travel of the shaft 13 will be directly related to the angular deviation of the hou's-, ing I from a vertical disposition, and a single pressure signal will be induced in the drilling fluid stream for each increment of angular deviation.

As indicated above, the range of angular deviation at which the instrument may respond is adjustable in response to rotation of the housing part 24 relative to the upper housing tion 30, whereby to axially shift stop ring supporting sleeve 17a relative to the pendulum 16. As seen in FIGS. 2b and 2c. the housing part 24 is provided with an internal thread 24a. This internal thread 24a engages in a helical groove 24!: in a connector sleeve 24c disposed within part 24 and slidably mounted on the upper housing section 30. Referring to FIG. 20, it will be noted that the sleeve 24: is connected by means of a fastener 24d to a collar 240 from which depend the abovenoted rods 23 which extend downwardly through block 63 (see FIG. 5) and are connected to the pins 17!).

The angular disposition of the part 24 relative to the upper housing section 30 thus determines the relative axial disposition of the stop rings 17s in the lower housing section 37. In

this manner in the extreme lowermost position of axial adjustment, rings 17e will be disposed for engagement of stop shoulders 275 through 2750 by the pendulum 16, but in the event that the instrument is to be adjusted for detection of angular deviation ranging between say 3-9? and 7", if shoulders 275 through 2750 represent detection of angles ranging between (l to 3-bit, the part 24 may be adjusted to move the stop shoulders upwardly so that a second set of stop shoulders 375 through 375f may be disposed for engagement by the pendulum 16. It will also be understood that the range of adjustment of the stop shoulders provided by rings 17a may be such that any combination of stop shoulders 2750 through 375 may be availed for the purpose of detecting angular deviation within any selected range of the maximum range for which the instrument is adapted by provision of stop rings 17a of different diameters.

In order to fix the selected range, the rods 23 are provided with a series of axially spaced depressions 23a with which cngage detent means 23!; which, in the illustrative embodiment, comprises a spring ring disposed about the block 63 in a groove 23c, as best seen in FIGS. 20, 3, and 5. On the upper housing section 30 is fixed, as by fastener 30a (FIG. 2b), a collar 30b having a suitable index means 30c which, in relation to 'graduations 30d on the upper end of the rotatable part 24, will serve to indicate the relative axial disposition of the stop ring support sleeve 17a within the lower housing section 37. By virtue of this construction, the instrument may be preset so as to detect angular deviation ranging from 0 deviation through any selected range of the entire capability of theinstrument, for example, either from 0 to 3V? or 2 to 5 1?, etc.

In use, the instrument as described above operates so as to indicate to the person controlling the progression of a well drilling operation the angle at which the drill collar string immediately above the drill bit is disposed each time the driller stops the drilling operation so that an additional length of drill pipe may be added to the drill string. This indication is derived inherently due to the fact that the circulation of drilling fluid is temporarily arrested. During the period that such circulation is halted, the shaft 13 and the knob 14 will move upwardly through a number of pulse rings representative of the angular disposition of the drill collar S above the drill bit. In addition. if the driller so desires he may intermittently halt the circulation of drilling fluid so as to derive, at will, an indication of the angular disposition of the drill string above the drill bit.

Upward movement of the knob 14 is limited by engagement of the shaft stop 77 with the stop ring 75 on tube 61 or with one of the sets of balls 75a through 75f, depending upon which of the stop shoulders of the stop means 17 has been engaged by the pendulum 16. Therefore, upon resumption of the circulation of drilling fluid the knob 14 will move downwardly through a number of the pulse rings 7 representative of the increments of angular deviation, so that pressure signals will be induced in the stream of drilling fluid to be detected by surface pressure gauge or surface pressure recorder means to indicate to the driller the angular disposition of the drill string above the drill bit. At the point in this operation at which the circulation of drilling fluid is arrested and the upward move ment of the shaft 13 is arrested by engagement of the stop shoulder 77 with the selected balls 75a through 75f, the latch means will have been released and the pendulum will be on its seat, but upon resumption of circulation of drilling fluid the downward movement of the shaft 13 and the resultant downward movement of the coding rod 60 will cause the latch means to again be engaged with the pendulum connecting rod 90, providing that the coding rod 60 moves downwardly a sufficient distance to assure that the latch finger 98 will reengage the latch shoulder 94, as shown in dotted lines in FIG. 4. The forces resisting such downward movement of the coding rod 60 and the latch means include the opposing force of the spring 110 within the pendulum connecting rod 90 which urges the latch body 95 upwardly, the spring 60a within the coding rod guide tube 6] which acts upwardly on the coding rod, the main spring and the spring 70!; interposed between the upper end of the coding rod 60 and the shaft 13. Therefore, in order to be certain that sufficient downward force on the knob 14 is provided in response to the pressure difference acting on the knob 14, the above-described replaceable bushing A is selected to provide a diameter of the wall 5f therefor which will cooperate with the outer periphery of the knob 14 to provide an annular gap or flow passage 5i related to the proposed rate of drilling fluid flow in the drilling operation. Where large drilling fluid flows are to be employed, the diameter of the wall 5 f of the replaceable bushing A therefore may be larger than when the drilling operation will involve low fluid flow volume. ln this connection, the bushing may be selected and installed in the pulse ring tube support 5 so as to provide a flow path or gap 51' which has a lesser area than the flow area provided between the pulse rings 7 which must be large, as compared with the flow area defined between the knob 14 and the pulse rings 7, if discrete pressure pulses are to be produced in the stream of drilling fluid which can be readily distinguished by recording instruments at the earth's surface.

While the specific details of an illustrative embodiment of the invention have been herein shown and described, changes and alterations may be resorted to without departing from the spirit of the invention as defined in the appended claims.

lclaim:

1. In a signalling apparatus adapted to be installed in a well drilling string for producing signals in a stream of well drilling fluid indicative of the disposition of the drilling string in the well bore, said apparatus comprising: an elongated housing. a shaft longitudinally movable outwardly from and inwardly to an innermost position, said shaft having a free end projecting from said housing, means in said housing for biasing said shaft outwardly from said innermost position. means for limiting outward movement of said shaft to'an extent determined by disposition of said housing in the well bore, and signal producing means for producing a number of pressure pulses in the stream of drilling fluid depending upon the extent of outward movement of said shaft, said si nal producing means includin 1 a knob on the free end of said s aft, seal means carried by sat housing for slidably sealing said shaft to said housing substantially where said free end projects from said housing. a pulse tube having a central flow path and axially spaced pulse rings circumscribing said flow path and defining annular spaces between adjacent pulse rings, said pulse rings forming restricted flow paths past said knob when said knob is disposed adjacent said pulse rings, and means positioned inwardly of the last pulse ring for restricting the flow of fluid past said knob following movement of said knob past the last pulse ring during inward movement of said shaft to provide a greater differential fluid pressure acting on said knob to force the shaft to said innermost position, in which the portion of said shaft that is slidably sealed to said housing by said sealing means is protected by said housing from erosive action of the drilling fluid.

2. Signalling apparatus as defined in claim 1 wherein said means further restricting the flow of fluid past said knob includes a bushing positioned inwardly of said last pulse ring and circumscribing said flow path, said bushing having an inside diameter greater than that of said pulse rings but less than that of the pulse tube between said pulse rings.

3. Signalling apparatus as defined in claim 2 wherein said bushing has an inner wall composed of erosion-resistant material.

4. Signalling apparatus as defined in claim I. wherein said means further restricting the flow of fluid past said knob includes a bushing positioned inwardly of said last pulse ring and circumscribing said flow path, said bushing having an inside diameter greater than that of said pulse rings but less than that of the pulse tube between said pulse rings, and including means removably supporting said bushing.

5. Signalling apparatus as defined in claim I, wherein said means further restricting the flow of fluid past said knob includes a cylindrical member positioned inwardly of said last pulse ring and circumscribing said flow path, said cylindrical member having an inside diameter greater than that of said pulse rings but less than that of said pulse tube between said pulse rings. 

1. In a signalling apparatus adapted to be installed in a well drilling string for producing signals in a stream of well drilling fluid indicative of the disposition of the drilling string in the well bore, said apparatus comprising: an elongated housing, a shaft longitudinally movable outwardly from and inwardly to an innermost position, said shaft having a free end projecting from said housing, means in said housing for biasing said shaft outwardly from said innermost position, means for limiting outward movement of said shaft to an extent determined by disposition of said housing in the well bore, and signal producing means for producing a number of pressure pulses in the stream of drilling fluid depending upon the extent of outward movement of said shaft, said signal producing means including a knob on the free end of said shaft, seal means carried by said housing for slidably sealing said shaft to said housing substantially where said free end projects from said housing, a pulse tube having a central flow path and axially spaced pulse rings circumscribing said flow path and defining annular spaces between adjacent pulse rings, said pulse rings forming restricted flow paths past said knob when said knob is disposed adjacent said pulse rings, and means positioned inwardly of the last pulse ring for restricting the flow of fluid past said knob following movement of said knob past the last pulse ring during inward movement of said shaft to provide a greater differential fluid pressure acting on said knob to force the shaft to said innermost position, in which the portion of said shaft that is slidably sealed to said housing by said sealing means is protected by said housing from erosive action of the drilling fluid.
 2. Signalling apparatus as defined in claim 1 wherein said means further restricting the flow of fluid past said knob includes a bushing positioned inwardly of said last pulse ring and circumscribing said flow path, said bushing having an inside diameter greater than that of said pulse rings but less than that of the pulse tube between said pulse rings.
 3. Signalling apparatus as defined in claim 2 wherein said bushing has an inner wall composed of erosion-resistant material.
 4. Signalling apparatus as defined in claim 1, wherein said means further restricting the flow of fluid past said knob includes a bushing positioned inwardly of said last pulse ring and circumscribing said flow path, said bushing having an inside diameter greater than that of said pulse rings but less than that of the pulse tube between said pulse rings, and including means removably supporting said bushing.
 5. Signalling apparatus as defined in claim 1, wherein said means further restricting the flow of fluid past said knob includes a cylindrical member positioned inwardly of said last pulse ring and circumscriBing said flow path, said cylindrical member having an inside diameter greater than that of said pulse rings but less than that of said pulse tube between said pulse rings. 